US military simulates nuclear detonation in low-Earth orbit

A high-altitude nuclear detonation (HAND) in low-Earth orbit (LEO) would have several critical technical effects:

• Electromagnetic Pulse (EMP): A HAND generates a powerful EMP that can instantly damage or disable electronics on satellites within its line of sight and cause widespread electrical grid disruptions on Earth, even hundreds of miles away from the detonation point.
• Artificial Radiation Belts: Detonations, such as the 1.4-megaton Starfish Prime at 400 km altitude, significantly increase the intensity of Earth's natural Van Allen radiation belts. These enhanced belts trap high-energy electrons for years, leading to severe, long-term radiation damage to satellites.
• Satellite Damage Mechanisms: Satellites are vulnerable to prompt radiation (X-rays, gamma rays, neutrons) and delayed effects from trapped electrons. This radiation can damage solar arrays, sensitive electronics, and timing systems. A detonation of 110 kilotons or greater could jeopardize up to 20% of LEO satellites from prompt radiation, with delayed effects impacting others for weeks, months, or even years.
• Debris Generation: While a nuclear explosion in orbit would not produce a mushroom cloud due to the lack of atmosphere, it would generate massive amounts of debris. This debris could initiate a Kessler Syndrome, where collisions create more fragments, potentially making entire orbital bands unusable for decades.
• Communication Interference: A detonation could interfere with radio communications between the ground and satellites locally for minutes to hours, significantly degrading space-based communications, remote sensing, and weather services.